摘要:

AbstractThe testis of the newt,Trituroides hongkongensisis found to be made up of a chain of lobes each being divided into spermatogenetic zones which display seasonal cycles. Seasonal changes in the histology of the testis are studied. Lobule boundary cells are found present at the same time of the year when the secondary sex character, a lateral blue line along the tail, is best expressed. Both 5‐ene‐3β‐ and 17β‐HSD activities have been located in the lobule boundary cells which are suggested to be steroidogenic and their secretion may probably be responsible for the maintenance of the secondary sex character. The Sertoli cell, which originates from the follicle cell, shows accumulation of cholesterol‐positive lipid at certain stages of development but its capability in hormone production i

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1977.tb00230.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractAn electron microscopical study was made on the lobule boundary cells. They were found to show characteristic ultrastructures of a typical steroid‐producing cell. Changes in these cells were divided into five stages according to the development within the lobules. The possible significance of the changes and their correlation with the degree of steroid production at different stages are discusse

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1977.tb00231.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractUltrastructure of the somatic components of the testis of the Pacific hagfish was studied. Interstitial cells, equivalent to Leydig cells of higher vertebrates, containing smooth‐surfaced endoplasmic reticulum and mitochondria with tubular cristae were found in the interstitial tissue, as well as leucocytes, fibroblasts and other cells of unknown role. Two kinds of somatic cells were observed in the testicular follicles: Sertoli cells and “stellate cells”. The significance of interstitial cells was discussed in relation to possible involvement in steroidoge

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1977.tb00232.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractUltrastructure of the ovary of the Pacific hagfish was studied. Attention was paid to the mesovarium, small oocytes, oocytes of intermediate size, large oocytes, postovulatory follicles shortly after ovulation, postovulatory follicles considerably after ovulation, and preovulatory atretic follicles. The progressive changes of thecal and granulosa layers in the course of egg development and degeneration are described. No cells showing the ultrastructural characteristics associated with steroidogenesis were found.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1977.tb00233.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe distribution of succinic dehydrogenase activity was investigated in the pectoralis muscle of thirteen East African birds, representing five Orders. It was found that the pectoralis muscle of the most primitive birds studied (Galliformes) contained all “white” muscle fibres whereas the more advanced birds (Passeriformes) had all “red” muscle fibres. Intermediate Orders had mostly a mixture of red and white muscle fibres. There also appeared to be a direct relationship between body size and average muscle fibre size. However, it was concluded that the most important factor in relation to the muscle structure is the bird's mode of flight. The relationship with the degree of evolution and body size only held true in so far as the birds which had developed the facility for sustained flight, by increasing their red muscle fibre content, were also smaller in size and constituted the more “evolved” Orders of birds. In support of this it was noted that migratory birds (i.e. engaging in sustained flight) from more primitive Orders also had a high red muscle fibre content in their pectora

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1977.tb00234.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe are two morphological types of mesenchyme cells, bipolar and multipolar, and both are derived from the tip of the archenteron at the gastrula stage. Some of the cells form larval muscle and others may be involved in the stomodeum and coelomic pouch formation.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1977.tb00235.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractFemale bats were housed singly or in groups and maintained at 5° or 23 °C. Red blood cell life spans were determined utilizing the disappearance of labeled sodium chromate (Cr51). Red cell counts, hematocrits, reticulocyte percentages and diameters, white cell differentials, and spleen histology were determined for bats subjected to three weeks of stress treatment. Isolated animals (warm and cold) had significantly lower hematocrits and red cell counts and significantly higher reticulocyte diameters and percentages than grouped bats. Random destruction of erythrocytes was initially higher in isolated bats. In cold and isolated animals the white pulp of the spleen was most reduced in quantity and in proliferative activity. Red pulp became highly engorged with erythrocytes and showed a hypertrophy of reticuloendothelial elements. Higher rates of random destruction are closely correlated with increased splenic erythrophagocytosis. Gold or isolation imposed separately are mild stress factors in little brown bats, while a severe stress response occurs when the two stressors are imposed simultaneousl

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1977.tb00236.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1977.tb00237.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY